http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
A thermal design method for the performance optimization of multi-stream plate-fin heat exchangers
Zhe Wang,Fenghui Han,Bengt Sundén,Yanzhong Li 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.6
An optimization design method based on field synergy principle is developed for Multi-stream plate-fin heat exchangers (MPHEs)with a segmented differential model. The heat exchanger is divided into a number of sub-exchangers along the main stream, and eachsub-exchanger consists of N passages along the height of the exchanger. Compared with the traditional heat exchanger design, this methodallows temperature and pressure fields to be obtained via coupling calculation with consideration of variable physical properties andthe axial heat loss of the heat exchanger. Finally, the heat exchanger is optimally designed using a temperature-difference uniformityoptimization factor based on field synergy principle. This design model can provide an accurate temperature field and pressure field,because the stream properties are determined by the mean temperature and pressure of each local sub-exchanger. Optimum results indicatethat the temperature distribution on the cross section of the heat exchanger is relatively uniform and that the temperature differenceof heat transfer for each stream is always a small value. These characteristics prove the feasibility and effectiveness of this design model. In this paper, a case of five stream plate-fin heat exchangers for an ethylene plant is designed under a practical cold box operating conditionwith the proposed model, the structure and heat transfer of which are optimally determined. The design model and optimizationmethod proposed in this work can provide theoretical and technical support to the optimization design of MPHEs.
Yongliang Wang,Rongxin Ma,Lizhu Liu,Zhanchun Xu,Fenghui Li 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2017 NANO Vol.12 No.8
As one of the electrode materials for supercapacitor, Co3O4/graphene composite was mainly synthesized via two-steps method. Here, a facile one-pot method was used for Co3O4/graphene composite, and the performances of one-pot-synthesized Co3O4/graphene composite were carefully investigated. Liquid-phase exfoliation was used for graphene and the D-band/G-band ratio of liquid-phase exfoliated graphene was only 0.094, which indicated that the graphene had low defect density and enhanced electrical conductivity. Morphologies investigation of Co3O4/graphene composites indicated that Co3O4 nanoparticles with mean diameter of 14 nm were uniformly anchored on graphene sheets. The facile one-pot method associated with liquid-phase exfoliated graphene induced Co3O4/graphene composite with enhanced specific capacitance of 392 F · g -1 at a current density of 1 A · g -1. The Co3O4/graphene composite also expressed relatively small internal resistance and diffusion resistance (0.36 Ω and 0.45 Ω, respectively). Moreover, the synthesized Co3O4/graphene composite yielded excellent rate performances with only 9.5% capacitance loss when current density was increased by a factor of 10.
SSR and SCAR mapping of a multiple-allele male-sterile gene in Chinese cabbage (Brassica rapa L.)
Feng, Hui,Wei, Peng,Piao, Zhong-Yun,Liu, Zhi-Yong,Li, Cheng-Yu,Wang, Yu-Gang,Ji, Rui-Qin,Ji, Shu-Juan,Zou, Ting,Choi, Su-Ryun,Lim, Yong-Pyo Springer-Verlag 2009 TAG. Theoretical and applied genetics. Theoretisch Vol.119 No.2